* [PATCH] tpm: tpm_tis: Add optional delay after relinquish
@ 2026-05-19 6:09 Jim Broadus
2026-05-19 13:38 ` Jim Broadus
2026-05-21 23:48 ` Jarkko Sakkinen
0 siblings, 2 replies; 3+ messages in thread
From: Jim Broadus @ 2026-05-19 6:09 UTC (permalink / raw)
To: linux-integrity, linux-kernel, linux-doc
Cc: peterhuewe, jarkko, jgg, Jim Broadus
Some TPMs fail to grant locality when requested immediately after being
relinquished. In this case, the TPM_ACCESS_REQUEST_USE bit of the
TPM_ACCESS register is cleared immediately without setting
TPM_ACCESS_ACTIVE_LOCALITY.
This issue can be seen at boot since tpm_chip_start, called right
after locality is relinquished, fails. This causes the probe to fail:
tpm_tis MSFT0101:00: probe with driver tpm_tis failed with error -1
This occurs on some older Dell Latitudes and maybe others. To work
around this, add a "settle" boolean param to tpm_tis. When this is
enabled, a delay is added after locality is relinquished.
Signed-off-by: Jim Broadus <jbroadus@gmail.com>
---
Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
drivers/char/tpm/tpm_tis.c | 7 +++++++
drivers/char/tpm/tpm_tis_core.c | 3 +++
drivers/char/tpm/tpm_tis_core.h | 1 +
4 files changed, 18 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4d0f545fb3ec..5b7111033fbb 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7651,6 +7651,13 @@ Kernel parameters
defined by Trusted Computing Group (TCG) see
https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
+ tpm_tis.settle= [HW,TPM]
+ Format: <bool>
+ When enabled, this adds a delay after locality is
+ relinquished. Some TPMs will fail to grant locality if
+ requested immediately after being relinquished. This
+ causes the probe to fail.
+
tp_printk [FTRACE]
Have the tracepoints sent to printk as well as the
tracing ring buffer. This is useful for early boot up
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 9aa230a63616..8ac0ea78570e 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -101,6 +101,10 @@ module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
#endif
+static bool settle;
+module_param(settle, bool, 0444);
+MODULE_PARM_DESC(settle, "Add settle time after relinquish");
+
#if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
static int has_hid(struct acpi_device *dev, const char *hid)
{
@@ -242,6 +246,9 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
if (itpm || is_itpm(ACPI_COMPANION(dev)))
set_bit(TPM_TIS_ITPM_WORKAROUND, &phy->priv.flags);
+ if (settle)
+ set_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &phy->priv.flags);
+
return tpm_tis_core_init(dev, &phy->priv, irq, &tpm_tcg,
ACPI_HANDLE(dev));
}
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 21d79ad3b164..68be26fa5817 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -184,6 +184,9 @@ static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l)
__tpm_tis_relinquish_locality(priv, l);
mutex_unlock(&priv->locality_count_mutex);
+ if (test_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &priv->flags))
+ tpm_msleep(TPM_TIMEOUT);
+
return 0;
}
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index 6c3aa480396b..413cac5e0f31 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -90,6 +90,7 @@ enum tpm_tis_flags {
TPM_TIS_DEFAULT_CANCELLATION = 2,
TPM_TIS_IRQ_TESTED = 3,
TPM_TIS_STATUS_VALID_RETRY = 4,
+ TPM_TIS_SETTLE_AFTER_RELINQUISH = 5,
};
struct tpm_tis_data {
--
2.54.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] tpm: tpm_tis: Add optional delay after relinquish
2026-05-19 6:09 [PATCH] tpm: tpm_tis: Add optional delay after relinquish Jim Broadus
@ 2026-05-19 13:38 ` Jim Broadus
2026-05-21 23:48 ` Jarkko Sakkinen
1 sibling, 0 replies; 3+ messages in thread
From: Jim Broadus @ 2026-05-19 13:38 UTC (permalink / raw)
To: linux-integrity, linux-kernel, linux-doc; +Cc: peterhuewe, jarkko, jgg
I realize the delay should be moved to __tpm_tis_relinquish_locality.
I'll change that in a v2 patch.
On Mon, May 18, 2026 at 11:09 PM Jim Broadus <jbroadus@gmail.com> wrote:
>
> Some TPMs fail to grant locality when requested immediately after being
> relinquished. In this case, the TPM_ACCESS_REQUEST_USE bit of the
> TPM_ACCESS register is cleared immediately without setting
> TPM_ACCESS_ACTIVE_LOCALITY.
>
> This issue can be seen at boot since tpm_chip_start, called right
> after locality is relinquished, fails. This causes the probe to fail:
>
> tpm_tis MSFT0101:00: probe with driver tpm_tis failed with error -1
>
> This occurs on some older Dell Latitudes and maybe others. To work
> around this, add a "settle" boolean param to tpm_tis. When this is
> enabled, a delay is added after locality is relinquished.
>
> Signed-off-by: Jim Broadus <jbroadus@gmail.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
> drivers/char/tpm/tpm_tis.c | 7 +++++++
> drivers/char/tpm/tpm_tis_core.c | 3 +++
> drivers/char/tpm/tpm_tis_core.h | 1 +
> 4 files changed, 18 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4d0f545fb3ec..5b7111033fbb 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -7651,6 +7651,13 @@ Kernel parameters
> defined by Trusted Computing Group (TCG) see
> https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
>
> + tpm_tis.settle= [HW,TPM]
> + Format: <bool>
> + When enabled, this adds a delay after locality is
> + relinquished. Some TPMs will fail to grant locality if
> + requested immediately after being relinquished. This
> + causes the probe to fail.
> +
> tp_printk [FTRACE]
> Have the tracepoints sent to printk as well as the
> tracing ring buffer. This is useful for early boot up
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index 9aa230a63616..8ac0ea78570e 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -101,6 +101,10 @@ module_param(force, bool, 0444);
> MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
> #endif
>
> +static bool settle;
> +module_param(settle, bool, 0444);
> +MODULE_PARM_DESC(settle, "Add settle time after relinquish");
> +
> #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
> static int has_hid(struct acpi_device *dev, const char *hid)
> {
> @@ -242,6 +246,9 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
> if (itpm || is_itpm(ACPI_COMPANION(dev)))
> set_bit(TPM_TIS_ITPM_WORKAROUND, &phy->priv.flags);
>
> + if (settle)
> + set_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &phy->priv.flags);
> +
> return tpm_tis_core_init(dev, &phy->priv, irq, &tpm_tcg,
> ACPI_HANDLE(dev));
> }
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 21d79ad3b164..68be26fa5817 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -184,6 +184,9 @@ static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l)
> __tpm_tis_relinquish_locality(priv, l);
> mutex_unlock(&priv->locality_count_mutex);
>
> + if (test_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &priv->flags))
> + tpm_msleep(TPM_TIMEOUT);
> +
> return 0;
> }
>
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 6c3aa480396b..413cac5e0f31 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -90,6 +90,7 @@ enum tpm_tis_flags {
> TPM_TIS_DEFAULT_CANCELLATION = 2,
> TPM_TIS_IRQ_TESTED = 3,
> TPM_TIS_STATUS_VALID_RETRY = 4,
> + TPM_TIS_SETTLE_AFTER_RELINQUISH = 5,
> };
>
> struct tpm_tis_data {
> --
> 2.54.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tpm: tpm_tis: Add optional delay after relinquish
2026-05-19 6:09 [PATCH] tpm: tpm_tis: Add optional delay after relinquish Jim Broadus
2026-05-19 13:38 ` Jim Broadus
@ 2026-05-21 23:48 ` Jarkko Sakkinen
1 sibling, 0 replies; 3+ messages in thread
From: Jarkko Sakkinen @ 2026-05-21 23:48 UTC (permalink / raw)
To: Jim Broadus; +Cc: linux-integrity, linux-kernel, linux-doc, peterhuewe, jgg
On Mon, May 18, 2026 at 11:09:26PM -0700, Jim Broadus wrote:
> Some TPMs fail to grant locality when requested immediately after being
> relinquished. In this case, the TPM_ACCESS_REQUEST_USE bit of the
> TPM_ACCESS register is cleared immediately without setting
> TPM_ACCESS_ACTIVE_LOCALITY.
>
> This issue can be seen at boot since tpm_chip_start, called right
> after locality is relinquished, fails. This causes the probe to fail:
>
> tpm_tis MSFT0101:00: probe with driver tpm_tis failed with error -1
>
> This occurs on some older Dell Latitudes and maybe others. To work
> around this, add a "settle" boolean param to tpm_tis. When this is
> enabled, a delay is added after locality is relinquished.
>
> Signed-off-by: Jim Broadus <jbroadus@gmail.com>
It would be better idea first to replace priv->manufacturer_id with
priv->did_vid, and make necessary changes to sites where it is used.
Then in the if-statement compare DID/VID of the device to priv->did_vid
and apply quirk only if it matches.
> ---
> Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
> drivers/char/tpm/tpm_tis.c | 7 +++++++
> drivers/char/tpm/tpm_tis_core.c | 3 +++
> drivers/char/tpm/tpm_tis_core.h | 1 +
> 4 files changed, 18 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4d0f545fb3ec..5b7111033fbb 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -7651,6 +7651,13 @@ Kernel parameters
> defined by Trusted Computing Group (TCG) see
> https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
>
> + tpm_tis.settle= [HW,TPM]
> + Format: <bool>
> + When enabled, this adds a delay after locality is
> + relinquished. Some TPMs will fail to grant locality if
> + requested immediately after being relinquished. This
> + causes the probe to fail.
> +
> tp_printk [FTRACE]
> Have the tracepoints sent to printk as well as the
> tracing ring buffer. This is useful for early boot up
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index 9aa230a63616..8ac0ea78570e 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -101,6 +101,10 @@ module_param(force, bool, 0444);
> MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
> #endif
>
> +static bool settle;
> +module_param(settle, bool, 0444);
> +MODULE_PARM_DESC(settle, "Add settle time after relinquish");
> +
> #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
> static int has_hid(struct acpi_device *dev, const char *hid)
> {
> @@ -242,6 +246,9 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
> if (itpm || is_itpm(ACPI_COMPANION(dev)))
> set_bit(TPM_TIS_ITPM_WORKAROUND, &phy->priv.flags);
>
> + if (settle)
> + set_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &phy->priv.flags);
> +
> return tpm_tis_core_init(dev, &phy->priv, irq, &tpm_tcg,
> ACPI_HANDLE(dev));
> }
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 21d79ad3b164..68be26fa5817 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -184,6 +184,9 @@ static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l)
> __tpm_tis_relinquish_locality(priv, l);
> mutex_unlock(&priv->locality_count_mutex);
>
> + if (test_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &priv->flags))
> + tpm_msleep(TPM_TIMEOUT);
> +
> return 0;
> }
>
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 6c3aa480396b..413cac5e0f31 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -90,6 +90,7 @@ enum tpm_tis_flags {
> TPM_TIS_DEFAULT_CANCELLATION = 2,
> TPM_TIS_IRQ_TESTED = 3,
> TPM_TIS_STATUS_VALID_RETRY = 4,
> + TPM_TIS_SETTLE_AFTER_RELINQUISH = 5,
> };
>
> struct tpm_tis_data {
> --
> 2.54.0
>
BR, Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-05-19 6:09 [PATCH] tpm: tpm_tis: Add optional delay after relinquish Jim Broadus
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2026-05-21 23:48 ` Jarkko Sakkinen
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